This application relates the art of electrical boxes and, more particularly, to electrical mud boxes for use in poured concrete construction. The application particularly concerns electrical mud box assemblies of the type that include adapters and will be described with specific reference thereto. However, it will be appreciated that the application has broader aspects and that certain features can be used in electrical boxes that do not have adapters.
Because steel forms are used in tunnel forming of vertical concrete walls, fasteners such as nails or screws cannot be used to attached electrical boxes to the inside surface of the forms. Therefore, the electrical boxes commonly are attached to reinforcing bars before the forms are in place. It is very difficult, if not impossible, to maintain the open end of the electrical box in sealed engagement with the inner surface of a steel form to prevent poured concrete from entering the box. The open end of the box sometimes is closed with duct tape and the box cavity sometimes is filled with plastic foam that subsequently must be removed.
The steel forms typically are at least ten feet high, and the poured concrete develops significant hydraulic pressure that forces concrete to flow into the box cavity.
It would be desirable to provide an improved arrangement for closing the open end of an electrical mud box to prevent ingress of poured concrete while providing easy access to the box cavity when the concrete has cured and the forms are removed.